J.R. Smith could agree to terms with the Knicks tomorrow on a four-year, $24.7 million deal, according to his father.

The Knicks and Smith were “discussing’’ contract terms last night after none of the current offers on the table bowled Smith over, according to an NBA source.

But Earl Smith, J.R. Smith’s father, made it clear to The Post Smith still could change his mind if a new whopping offer comes down the pike tomorrow. That seems unlikely at this point.

Earl Smith also said any deal can’t be finalized today because the lawyers won’t be available on the July 4 holiday.

“I’m a diehard Knick fan, but I want to see my son get justice,’’ Earl Smith said last night. “We know the Knicks only have so much money because of early-Bird rights. But if some team offers a crazy amount of money, like $10 million per, he’ll probably go there. We’ll see what happens. He’s not signing yet.’’

Two of his suitors, the Rockets and Mavericks, are waiting to see if they will land Dwight Howard before making an offer for Smith tomorrow. The Rockets were considering a four-year package for Smith. There is no state income tax in Texas.

Earl Smith said another team’s offer has to be significantly higher than what the Knicks can offer. That is because Smith is sincere in wanting to stay in his hometown. He also wants to play with his brother, point guard Chris Smith, who will be on the Knicks summer league team and assuredly be given a roster spot if he shows no ill effects from left knee surgery. Chris Smith changed agents late this season, going with J.R.’s agent, Leon Rose, as part of an unofficial package deal.

Under the early-Bird rights, the Knicks only could offer four years, $24.7 million and that’s what Smith is expected to receive. That is a yearly average of nearly $6 million per season.

It is possible there will be a player option after his second season. Earl Smith said he son received a comparable offer but didn’t reveal from which club.

Under the early-Bird rights rules, the Knicks only were able to start Smith’s contract at the league’s average salary. Though the league audit won’t be completed until next week, it is expected to be $5.57 million, with 7.5 percent annual raises.

The Knicks prefer to sign Smith to a two-year package worth roughly $11.5 million. After the two years are up, Smith could then re-sign with the Knicks with full-Bird rights and get a maximum contract.

That sort of two-year structure surely would keep the flaky Smith motivated and also keep the Knicks potentially clear of contracts for the summer of 2015 when they may have to rebuild again and move under the salary cap.

The Knicks entered free agency confident they could re-sign Smith and were desperate because of their lack of flexibility in the free-agent market. Had the Sixth Man of the Year not elbowed Jason Terry in the first round and fallen apart from there, he assuredly would have gotten a deal averaging more than $9 million per season and be gone.

Milwaukee had Smith high on its list, but yesterday instead signed shooting guard O.J. Mayo. The Bucks got rebuffed by Kyle Korver and might be the team that extended Smith an offer that wasn’t spellbinding.

The Pistons, who are in the hunt for Andre Iguodala and Josh Smith, showed minimal interest as did Charlotte and Phoenix.

The Knicks are expected to lose Chris Copeland but are likely to re-sign their other free agent, Pablo Prigioni on a two-year deal for a portion of their mini mid-level exception. The Knicks still hope to sign Elton Brand for the rest of their mini mid-level and ink either Francisco Garcia or Matt Barnes for the $1.4 million veteran’s minimum.